Sealing composition



Patented Apr. 22, 1947 SEALING COMPOSITION Raul W- M llelot, .Jr.., Ma wood, 1-, a s to Ameri an Ca C m New k, a corporation of New Jersey :No Draw n 6 Claims.

My n ention re at s ene a ly to sea ills r pack ng .e m ositions and comprises more articularly a n vel and ec o ical eal nee mnositi o aske meter al or u e i the i n of th sea in fl es of san tarvsh et m al elon- 'taine svCon ainers o thi ty e are used lar ely i the packa i of ariou food produetssuth as v etab es, .fruits, eats, dr powders, etctand s h eonta ersmust be he m a ysealed a subst n ia vacuum roduced by a e. n I. the conten s o by direct vae um za on the eby ,eiie v v pre rv ng he duct. eelsed such con ainers for eomparativelylons M. ime. .Netura rubbe when pro erl t e t d, reeeseed 0r nded lesirahle ronlties tha rmake i a m ient an he metic sealnsmedi m tor fo d c ntain rs 'll eee esirah e pro e tie nc ud resilien elasti ity, p astic flow un er hea and pressure, .adhesion to metal, tack and resistance to corrosionand aging. Nate u l ubbe o its late probabl th mo wide use mat rial in seal ng com ound or h hermetic sea n o h et me aleo ta ners ior War nd ions r ndered it scarce and rit ca mat a n t se c fo a suitable s bstitu e nd af r extensi e xperim ntati n w th various materials, I discovered a s a in omn und, eonteining no atu a r r wh ch has proved se t onc c m ca n 'hishly effi ient a a gas e ining m e i or on ain r Joints es eally fo e e n o th te loeked'flanses of sheet metal container bodies and ends, gmmonly called double seams.

The pr n ipa ob c oi my n ention o is= cov y i t ro is on o a Seal n com osi ion h h al h u h n a ni g no natura rubber, a s a lly a he esir hle charact ri tics, p operties an ad anta s or" sea in .eomso nds in wh ch natu rub e la s a leading art uch as es lienee, last i y, plas icit adh sion and ack esistance to corrosion b f od acids allialiee, lts c, an resis an to a e se i n a d in addition is com arat e eeono mi cal and comparatively easy to prepare and to apply.

Numerous other objects and advantages of my-inventionwill be apparent as it is better um derstood from: the following detailed description which is a preferred embodiment of my inven- 'tion.

The sealing compound of my invention com- Anpl nDec niber 10, 19% .Se a 5.13319 inert, i e p and nelydi ded fil er andi desired an opacity producing pigment and also if desi d a or impartin pi ment and creams solvent or solvents and/or diluents which are nontoxic, have a comparatively low boiling range and are compatible -With;,th esolid ingredients.

I discovered that Hercules T ethyl cellulose gave the best results. Other grades o *Htl'filllfifi ethyl cellulose, with sli ht chan es i orm. tion and solvent alsosave satisf ctor es i also found that caster oil (A, A: rade a ver satisfactory and comparativelyinexpensive plasticizerjor the ethyl cellulose) Other non-drying plasticizers such as soybean oil (preferably cornbined with a lesser amount of soybean fatty acid) Hercoyln (hydrogenated methyl abiestate) and dibutyl pht-halaternay be used as suitable substitutes.

In order to obtain enhanced tackiness or adhesiveness of the compound I-found the addition of a resin extender such as Hercules Staybelite" not only compatible with ethyl cellulose but substantially essential.

While not essential, I found that for the sake of economy, a small percentage (not over 29%.-) of finely divided inert filler or fillers .did not adversely affect the desired properties of the sealing compound. I found Catalpo, a hydrous aluminum silicate, a product of Moore llz Munger, very satisfactory as a filler in my sealing composition. However, Multifex, a precipitated cal by fruit acids and is not recommended for acidic products,

When it is desired to impart opacity to the compound asmallpercentage oi titanium dioxide or s i ar aque pig en ma b dm For certain purposes it may also be desirable-to color the compound, in which case a trace or modicum of color pigment, such as carbon black, may b added,

When the sealing compound of the present invention is to beused to seal the joints or seams of ,food containers it is essential that only sanitary and non-toxic ingredients and solvents and/or diluents be used. Also because modern high speed container manufacture requires speedy dr n o co d line co i er Part t is desirable to employ low boiling solvents and/oi diluents. Also such solvents and diluents must effectively and compatibly dissolve or disperse the Percent Ethyl cellulose About 30-40 Plasticizer do -30 Resin extender do 1530 Filler and pigments do 10"20 The following four formulae have thus far given the best results:

Formula No. 1

. Percent Hercules T100 ethyl cellulose 36.36

A. A. castor oil 27.27

Hercules Staybelite resin 18.18

Catalpo 18.19

Formula, N0. 2

Percent Hercules T100 ethyl cellulose 36.36

A. A. castor oil 18.18

Hercules Staybelite resin 27.27

Catalpo 18.19

Formula No. 3

Percent Hercules T100 ethyl cellulose 36.36

Soybean oil 14.54:

Soybean fatty acids 3.64

Hercules Staybelite resin 27.27

Catalpo 14.55

Titanium dioxide 3.64

Carbon black Trace Formula No. 4

Percent Hercules T100 ethyl cellulose 40 A. A. castor oil Hercules Staybelite resin Catalpo" 8 Titanium dioxide 2 Carbon black"; Modicum to about 23 percent total solids in a mixture of 85 percent n-hexane and 15 percent ethyl acetate. For efficient solvent action on this grade of ethyl cellulose the proportion of ethyl acetate should not be under 10 percent.

N-100 grade of Hercules ethyl cellulose would be a suitable substitute for the T-100 grade given in the examples, in which case, however, a higher ratioof ethyl acetate (solvent) to n-hexane (diluent) in the solvent mixture is recommended. The T grade of Hercules Ethyl Cellulose has an ethoxyl content of 48.5 to percent and the N- grade an ethoxyl content of 46.8 to 48.5 percent.

In preparing my novel, non-rubber sealin compound for the lining of container joints, I have found either of the following two methods to be satisfactory:

I call the first method the dry or milling method. By this method the solid ingredients (including the plasticizer) are worked together into a fairly homogeneous mass on a rubber mill. The ethyl cellulose is first sheeted out by means of cool, tight rolls together with a small initial quantity of plasticizer to prevent the stock being worked from becoming too brittle. Then the plasticizer (castor oil, soybean oil, etc.) and the Staybelite resin are worked into the mass until a smooth sheet is formed. When desired or needed, fillers and pigments are incorporated into the stock last. This mixture requires but one milling since the sole purpose of the milling is to disperse the filler and pigment particles uniformly among the particles of ethyl cellulose, the plasticizer and resin. The compound stock is next cut up into small pieces, dissolved in a suitable mixture of petroleum naphtha (boiling range: -160 degrees F.) and ethyl acetate and mixed into a smooth solution. The liquid compound is then brought to lining viscosity by adding additional solvents (if necessary) and strained, and is then ready for the lining or coating operation.

The second method of preparing the sealing compound of my invention I have called the wet or solvent method. It is accomplished without the use of a rubber mill and is, therefore, less expensive. It consists in first dissolving the ethyl cellulose (in granular or powder form) in a mixture of suitable solvents and plasticizer in avessel or tank preferably with the aid of a power mixer, followed by the addition of the Staybelite resin (preferably ground or pulverized), fillers and pigments (if desired), preferably in the order named. When complete solution and homogeneous dispersion have been attained, the liquid compound is brought to lining viscosity and strained and is now ready to be used in the sealing compound applying machine.

This second method is satisfactory when the particle size of the fillers and pigments is sufficiently fine and the degree of wettability of the fillers and pigments by the solvents is 'sufliciently high to yield a fine dispersion.

The sealing compound prepared in accordance with the foregoing specifications is in liquid form and of such viscosity that it can be flowed or otherwise deposited onto the flanges of container parts by any conventionalv sealing compound lining machine. The lined container parts, such as sheet metal can ends, are then subjected to the usual and well known drying procedure.

While I have described my invention as primarily adapted to the sealing of sheet metal container joints, I do not wish to limit nfyself to this particular use, for it has or may have much wider application.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the use of ingredients and their proportions and in the steps of the process described and their order of accomplishment without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the novel composition and process hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A sealing composition for the lining of the I percent and a finely divided inert filler of not over 20 percent, said proportions being percentages by weight of said solid ingredients, said ingredients being dissolved and dispersed to proper lining viscosity by a non-toxic low boiling solvent.

2. A sealing composition for the lining of the joints of food containers and for similar purposes, which comprises in combination, a homogeneous mixture of ethyl cellulose in proportions of substantially 30 to 40 percent, a vegetable oil of the class consisting of castor oil and soy bean oil as a plasticizer in proportions of substantially to 30 percent, a hydrogenated rosin as a resin extender in proportions of substantially 15 to 30 percent and a finely divided inert filler of not ever percent, said proportions being percentages by weight of said solid ingredients, said ingredients being dissolved and dispersed to proper lining voscosity by a solvent mixture consisting of ethyl acetate and petroleum naphtha.

3. A sealing composition for the lining of the joints of food containers and for similar purposes,

which comprises in combination the following solid ingredients in percentages by weight:

, Per cent Hercules T100 ethyl cellulose 36.36 A. A. castor oil 27.27 Hercules Staybelite resin 18.18 Catalpo 18.19

Percent Hercules T100 ethyl cellulose 36.36 A. A. castor oil 18.18 Hercules Staybelite resin 27.27 Catalpo 18.19

dissolved and dispersed to proper lining viscosity by a non-toxic low boiling solvent.

5. A sealing composition for the lining of the joints of food containers and for similar purposes, which comprises in combination the following solid ingredients in percentages by weight:

Per cent Hercules T ethyl cellulose 36.36 Soybean oil 14.54 Soybean fatty acids 3.64 Hercules Staybelite resin 27.27 Catalpo 14.55 Titanium dioxide 3.64 Carbon black Trace dissolved and dispersed to proper lining viscosity by a non-toxic low boiling solvent.

6. A sealing composition for the lining of the joints of food containers and for similar purposes, which comprises in combination the following solid ingredients in percentages by weight:

Per cent Hercules T100 ethyl cellulose 40 A. A. castor oil 20 Hercules Staybelite resin 30 Catalpo 8 Titanium dioxide 2 Carbon black Modicum dissolved and dispersed to proper lining viscosity by a non-toxic low boiling solvent.

PAUL W. MILLELOT, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,327,862 Borglin Aug. 24, 1943 2,325,966 OLeary Aug. 17, 1943 2,179,339 Little Nov. 7, 1939 2,108,807 Finzel et a1. Feb. 22, 1938 2,075,376 Ubben Mar. 30, 1937 1,948,580 I-Iucks Feb. 27, 1934 2,362,166 Speicher Nov. 7, 1944 

